Device for preparing perspective views from orthogonal views

ABSTRACT

The device comprises a flat base plate, a drawing board at substantially right angles to the base plate, a guide rod having one end universally pivotally connected to a mounting in a tracing instrument carrying a tracing index located adjacent to the base plate, the mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, a shaft rotatable on a fixed axis extending parallel to the base plate, a universal joint on one end of the shaft in which the guide rod is slidably mounted, and a universal joint connecting the other end of the shaft to a rod extending parallel to the guide rod and having an end provided with a stylus for marking on the drawing board, the two rods being pivoted to the two ends of a coupling rod extending parallel to the shaft.

United States Patent Vermeulen [451 Apr. 25, 1972 [72] Inventor: Dirk Vermeulen, Pluvierloan 8, Endhoven, Netherlands [22] Filed: Apr. 1,1970

[21] Appl. No.: 24,498

[52] U.S. Cl. ..33/l8 C, 33/23 B [51] Int. Cl ..B43l 13/00 [58] FieldofSearch ..33/18C, 20C, 23 B, 24 R, 33/24 B, 24 C [5 6] References Cited UNITED STATES PATENTS 406,083 7/1889 Brix ..33/l8 C 888,249 5/1908 Meyer ..33/18 C 3,483,622 12/1969 Forster... .....33/23 B 2,317,052 4/1943 Hehr ..33/18 C FOREIGN PATENTS OR APPLICATIONS 71,703 2/1916 Switzerland ..33/1 8 C Primary ExaminerHarry N. Haroian Atlorney-Marshall & Yeasting [5 7] ABSTRACT The device comprises a flat base plate, a drawing board at substantially right angles to the base plate, a guide rod having one end universally pivotally connected to a mounting in a tracing instrument carrying a tracing index located adjacent to the base plate, the mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, a shaft rotatable on a fixed axis extending parallel to the base plate, a universaljoint on one end of the shaft in which the guide rod is slidably mounted, and a universal joint connecting the other end of the shaft to a rod extending parallel to the guide rod and having an end provided with a stylus for marking on the drawing board, the two rods being pivoted to the two ends of a coupling rod extending parallel to the shaft.

4 Claims, 7 Drawing Figures PATENTED APR 2 5 I972 SHEET 2 BF 3 DEVICE FOR PREPARING PERSPECTIVE VIEWS FROM ORTI-IOGONAL VIEWS The invention relates to a device for converting orthogonal views into perspective views.

It is often difficult to form from orthogonal views, especially when they indicate a large area as it is the case with drawings of roads, road crossings, planological and similar drawings, an idea of the situation as it will look in reality, for instance seen from the point of observation of an automobilist approaching a road crossing. It therefore happens that for solving difficult trafiic situations a tracing of a road crossing is designed which in an orthogonal drawing shows an easily surveyable situation, whereas it appears in practice that this situation is not easily surveyable for instance caused by perspective misdrawing of curves or right turn lanes, or by the application of guards or road signal posts which may hide for instance a curve or a right turn lane. In order to be able to judge the surveyability of a drawn road situation one must have much experience and a special insight to imagine an orthogonal drawing as a perspective view. It is therefore preferable to make a drawing in perspective in order to make a correct judgement.

However, it is practically impossible to produce beforehand exact perspective drawings of extensive areas presented in an orthogonal drawing as used by planologists and for building roads. Therefore in existing situations perspective drawings are made by using a transparent plate through which a draughtman observes the situation and draws this on the glass plate in order to obtain an image in perspective as exact as possible.

SUMMARY OF THE INVENTION The invention aims at permitting the production of an exact perspective drawing from an orthogonal drawing, i.e., before the work shown on the drawing has been carried out. This is possible with a device characterized according to the invention by a base plane and a projection plane over which last mentioned plane a marking stylus co-operating with a guide means is movable, the guide means being supported at a distance from the projection plane and above the base plane through universal joint means and being coupled to an index means movable along the base plane wherein the distance of a coupling point of the guide means from the base plane and/or the distance of the hinge point of the universal support from the base plane is adjustable. It is then preferable to construct the device according to the invention so that the projection plane forms an angle with the base plane.

A drawing with an orthogonal view may be fastened to the base plane and on the projection plane a sheet of paper may be fastened onto which with the intermediary of the marking stylus a perspective drawing may be marked. The marking points of the perspective drawing are obtained by detecting certain characteristic points of the orthogonal drawing by the index of a tracing means. The orthogonal drawing has to be fastened in such a way that the observation point for producing the perspective drawing which point has to be situated on the orthogonal drawing coincides with the hinge point of the guide means.

For this purpose the device according to the invention is constructed so that between the hinge point of the universal support of the guide means and the base plane a marking index has been provided for adjusting a view to be applied to the base plane. The adjustment of the drawing is obtained by having the observation point on the orthogonal view coincide with the marking index, the orthogonal view being adjusted so that the main direction of observation is substantially parallel to the direction of the guide means when this means occupies an intermediate position.

A. practical embodiment according to the invention is characterized in that the tracing means is movable with the aid of a separate guide along the base plane wherein the guide means for the marking stylus is provided as follower means for the tracing means. In this way an exact adjustment of the height of the marking stylus on the projection plane may be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of a road crossing;

FIG. 2 shows an orthogonal view of the road crossing shown in FIG. 1;

FIG. 3 shows a diagram of an observation point above an observation plane as seen vertically;

FIG. 4 shows a diagram based on FIG. 3 in which the principle of the device according to the invention is shown;

FIG. 5 shows a perspective view of a first embodiment of the device according to the invention;

FIG. 6 shows a schematic view of a detail of the device according to FIG. 5 and FIG. 7 shows a perspective view of a second embodiment of the device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 and 2, in the perspective view of FIG. 1 the observation point is placed at eye level above the ground in the right lane of a road near a traffic island. This observation point is indicated in FIG. 2 by the number 1. If a vehicle is present in said right lane and has to cross the crossing it will appear that the general view of the vehicle driver is insufficient and that he is not able to see to which point at the other side of the crossing he has to drive. This lack of survey clearly appears from FIG. 1 whereas from FIG. 2 it is evident that the driver in the right lane 2 will arrive in the right lane 2a at the other side of the road crossing. In the situation of FIG. 1 the right lane 2a at the other side of the crossing is fully hidden from sight. If a vehicle in the lane 2 wants to turn to the right in order to arrive at the lane 3 of the cross road it appears that the draw up bay 4 for the traffic turning to the right has been placed logically and effectively according to FIG. 2. However, on observation of FIG. 1 it appears that the draw up bay for the traffic turning to the right is fully hidden from sight and practically lies outside the field of observation of an arriving vehicle driver, especially because the draw up bay 4 is separated by a strip 5 for cyclists from the lane 2. The island 6 with the lantern post 7 placed on it form an obstruction to the observation of the draw up bay for the traffic turning to the right.

From the above but especially also from FIG. 1 and 2 it appears clearly that making exact perspective drawings from an orthogonal view, for instance of a road crossing as indicated in FIG. 2, is very desirable in order to provide a good impression before the start of the project. The same applies to viaducts and tunnels and to plans for extension in house-building and similar planological projects.

In order to permit the exact production of perspective views starting from an orthogonal view reference is made to FIG. 3. In FIG. 3 a base plane or ground is shown and indicated by reference number 8. The eye observation point has been indicated in FIG. 3 by the reference number la. The height h or eye level may be taken for an average observer standing on the base plane or ground 8 at 1.5 meters. The horizon always is at eye level so that an imaginary line 9 from the observation point 1a to the horizon always extends parallel to the base plane 8. If perpendicular to the base 8 in the field of observation a plane 10a or 10b is erected then the point of intersection of the planes 10a and 10b with the line 9, indicated by the reference numbers 11a and 11b respectively, indicates the height of the horizon above the base 8 at the planes 10a and 10b respectively. This means that for instance the point of intersection 11b lies at the same height h above the base 8 as the point of observation 1a. If a point 12 in the base 8 is situated at a distance a from the point of observation 10 then from the point 1a to the point 12 a radius vector 13 may be drawn. The same applies to the object point 14 lying at a distance b from the point of observation 1a. For this point 14 a radius vector 15 may be drawn. The vector 15, however, makes a smaller angle with the base 8 than the radius vector 13. The greater is the distance from the point of observation to an object point, the smaller are the angles of the radius vectors with the base plane or ground. If in the object point 12 an object with a height L is placed a radius vector 17 may be drawn to the upper point of the object at the height L above the base 8 which point has been indicated by the reference numeral 16. If the distance L is greater than the height h the point 16 will lie above the horizon line 9. All radius vectors intersect the plane a and when the relative points of intersection are connected to each other a perspective view of all object points on the base 8 and the points extending therefrom is obtained. The same applies if the radius vectors have to be extended up to the plane 10b.

If a plane is chosen between the point of observation 1a and the object points such as the plane 10a the points of intersection of the radius vectors intersection the plane 10a will form a perspective view smaller than the original drawing. If the plane is chosen beyond the area between the point of observation la and the object points, such as the plane 10b, the radius vectors will form a perspective view greater than the original drawing. However, the perspective ratios of the points of intersection of the radius vectors with a plane 100 and 10b remain equal.

Although with reference to FIG. 3 the perspective observation has been described in a vertical direction the same applies to the perspective observation in the horizontal direction. Based on the principles stated above, a base 18 (FIG. 4) may be formed onto which a drawing of for instance a road plan may be placed, e. g., on a scale of 1:500. If above this drawing, equally on scale, an observation point is placed this means that with a scale of 1:500 the point of observation is obtained at 3 mm above the base 18 for drawing radius vectors in the correct perspective ratio to the object points on the drawing. However, a small distance of 3 mm above the base 18 is not practical and therefore at a distance y to the base 18 an imaginary plane 18 may be drawn. In order to have the correct eye level of the point of observation 1b above this imaginary plane the point 1b has to be shifted to the point of observation 1c above the imaginary plane. This means that all object points in the drawing on the base 18 have to be shifted upwardly over the distance y. If from the point 10 radius vectors are drawn to all object points such as the points 12a and 14a elevated by the distance y said radius vectors will intersect a plane like 10a or 10b and if these points are connected correctly this plane will show a perspective view. Instead of shifting the point of observation 1c over a distance dy of for instance 3 mm above the imaginary plane 18 the point 10 may also be taken in the plane 18. The object points 12a and 14a then have to be detected at a height y-dy. If in the drawing on the base there has been indicated that from the object point 120 an object extends upwardly over a distance 1 then when detecting the object point 12a also the height may be added, i.e., the distance 1 divided by the scale ratio of the drawing. If the projection plane lies outside the area between the point of observation and the object points then when drawing to scale a sufficiently large perspective drawing is obtained on the projection plane. However, it is also possible to place the projection plane between the point of observation and the object points. In that case, however, a rather small perspective drawing is obtained.

On the basis of the above mentioned ideas it is possible to construct a device for converting orthogonal views into perspective views and a perspective view of said device according to the invention is shown in FIG. 5. A base 18 is constituted by a fiat plate and at one end of the plate a structure 19 has been provided supporting at its upper end a support 20 for a guide means 21. The support 20 is constructed such, for instance as a universal joint or as a self aligning precision journal, that the guide means constituted by a rod is adapted to move parallel to the base 18 and in a direction perpendicular thereto, the guide means pivoting in the support 20. The free end of the guide means 21 or rod is provided with a marking stylus 22 for a purpose hereunder to be described. In the perpendicular line from the pivot point of the support 20 to the base 18 an index means 23 is mounted for locating the point 24 on the base 18. This marking point 24 serves as point of observation and if a drawing is placed on the base 18 the point of observation to be chosen in the drawing has to lie exactly in point 24. Near the end of the base opposite to the structure 19 a projection plane has been provided constituted by a board 25, the marking stylus 22 of the guide means 21 being adapted to move along said board 25 when the guide means 21 is moved. On the board 25 a sheet of paper may be fastened and in order to permit the easy placing of said sheet the board is shiftable by means of guide sleeves 26a and 26b on guide rods 27a and 27b respectively, the board 25 being fixed by means of knobs 28. The guide rods 27a and 27b extending along the base 18 serve for guiding a bridge constituted by two guide sleeves 29a and 29b mutually connected by two guide rods 30. Along the said guide rods 30 a guide sleeve 31 is movable constituting the under part of the instrument 32 with which the object points in the drawing to be fastened on the base 18 may be detected. The guide sleeve carries a tracing index 33 for instance a transparent plate provided with a cross and may be shifted along the drawing on the base 18 for detecting its object points. Instead of a transparent plate 33 also a very small bright spot may be used for detecting the object points. Such a bright spot may be obtained by means of a lamp issuing a very concentrated light beam and producing a pip on the base 18. The guide sleeve 31 of the instrument 32 further carries two guide rods 34a and 34b extending perpendicular to the base 18. A yoke 35 is adjustable along said guide rods, namely approximately by means of a separate clamping piece 35a adapted to be fixed by a screw 36 on the rod 34b. If the screw 36 is loosened the yoke 35 may be manually shifted in an upward or downward direction. After fixing the screw 36 the yoke 35 may be adjusted by means of an adjustment screw 37 for fine adjustment with regard to the fixed clamping piece 35a. The yoke has an eye 38 constituting a coupling with the guide means 21. In order to obtain a coupling without play and to permit shifting the guide means 21 constituted by a rod pivotable in its support 20, the eye 38 is provided with a self aligning precision journal. The rod may be shifted in this journal when the instrument 32 is shifted along the guide rods 27a and 27b. The guide sleeve 31 of the instrument 32 carries a tower of blocks 39. The blocks may be shifted into two end positions around a rod 40. The height dimensions of said blocks have a very accurate value so that when a plurality of blocks 39 have been shifted in the direction of the eye 38 they provide in the tower a wide column on which the feeler of a measuring gauge 41 may rest. By means of a spring 42 positioned around the rod 40 the blocks 39 are pressed onto each other. By means of the blocks 39 and the gauge 41 the distance of the coupling point of the instrument 32 to the guide means 21 from the base 18 may be exactly adjusted and said adjusted distance corresponds to the distance y-dy as indicated in FIG. 4. After having detected for instance the object point 12a (FIG. 4) in the drawing on the base 18 the marking stylus 22 on the guide means 21 is actuated. The marking stylus is a writing-stylus or preferably a prick-pin because thereby the correct position may be indicated more exactly on the projection plane. The marking stylus 22 is preferably mounted in a plunger 43 fitting in a cylinder placed in the interior of the guide means 21. A connection 44 of a pressure fluid is provided on the guide means 21 so that via a hose and a pressure source the flowing fluid may be supplied to the cylinder of the plunger 43 or released therefrom whereby the stylus 22 will be displaced in an axial direction for actuating the marking stylus 22. This may also be obtained electrically for instance by means of a relay.

If by means of the marking stylus 22 the object point 12a has been projected onto the projection plane and an object with a height 1 is situated in the object point 12a then corresponding to the scale of the drawing on the base the yoke 35 is shifted. Therefore some blocks 39 of the tower are shifted in the direction of the eye 38 and thereby the yoke is correspondingly shifted in a vertical direction. The height is adjusted exactly by means of the gauge 41. The blocks 39 serve as an approximate adjustment and the exact adjustment is brought about by means of the said screw 37 and the gauge 41.

ln this manner all object points of the drawing may be detected and transmitted to the projection plane 25. Depending on the number of object points chosen said points may be interconnected by a line whereby an exact perspective view is obtained on the projection plane 25. If a great many of the object points are detected the interconnection of the points marked on the projection plane 25 will not be necessary because seemingly the whole drawing is executed by means of marking points. When the marking stylus 22 is a writing stylus then also lines in the drawing on the base 18 may be detected whereby also on the projection plane 25 lines will be obtained. Said last mentioned method, however, is less exact and requires a relatively great skill.

If the support 20 is made adjustable in vertical direction along a graduation one may adjust said support, i.e., the point of intersection of the axis of guide rod 21 with the axis of index means 23, corresponding to the chosen eye level. If, moreover,,by adjustment of eye 38 the imaginary base plane 18 is chosen such that the measuring gauge 41 or a graduation provided at this point indicates zero, then the heights of the objects of the drawing on base 18 divided by the scale ratio may be adjusted directly on the gauge, i.e., without first having to add said values to the value of y-dy which generally issues at an arbitrary number varying with the chosen eye level dy. This remains possible when a different eye level is chosen for another perspective drawing since said different eye level may be effected by an adjustment of support 20, the zero plane 18 remaining unchanged.

Hereby the ease of operation of the device is increased while errors and fatigue of the spirit, especially being present if subsequently drawings with different eye level have to be made, are obviated.

In the embodiment of the device according to the invention shown in FIG. 7 the guide means comprises two separate parts. The instrument 32 is shiftable by means of a separate guide rod 45 along the base 180 which may be a drawing board. The guide rod is shiftable in a sleeve 46 accurately pivotable by an annulus 47 in an opening of a mounting support 48. A gauge or index has been provided in the annulus 47 or in the opening in the mounting support 48 because under the point indicated by the index the point of observation of the drawing to be fastened on the base 18a has to be positioned. The mounting support 48 carries a sleeve 49 for supporting a rotatable shaft 50 also rotatably supported in a second sleeve 51 on an auxiliary mounting support 52. The shaft 50 has at its ends universal joints 53 and 54. The pivot point of the joint 53 is with regard to the base 18a situated perpendicularly above the index point in the annulus 47. The shaft 50 with the universal joints 53 and 54 constitutes the universal support for the guide means and therefore is comparable to the coupling 20 according to FIG. 5. The guide means 21a comprises in this embodiment two separate rods 55 and 56. The rod 55 has been coupled by means of a self aligning journal 59 to the instrument 32. The rod 55 is shiftable along its longitudinal direction through a sleeve 53a of the universal joint 53. The instrument 32 is provided with an index 57 for detecting the object points on the drawing on the base 18a. For easy handling of the instrument 32 a handle 58 is provided with push button 58a for actuating the marking stylus 22a at the free end of the rod 56 of the guiding means. Said rod 56 is shiftable and fixable in a sleeve 54a of the universal joint 54. By means of a knob 60 the rod 56 may be fixed in the sleeve 54.

Shifting the rod 56 of the guide means 210 is desirable to permit adjustment of the size of the perspective view to be obtained. The projection plane 25a co-operating with the marking stylus 22a has been mounted on a shiftable sleeve 61 and may be fixed by means of a knob 62 on a guide rod 63 mounted at the side of the drawing board. As the projection plane 25a is placed further from the universal joint 54 and correspondingly the rod 56 is adjusted in the sleeve 54a the size of the perspective view will increase. By adjusting the rod 56 and the projection plane 25a it is thus possible to choose the size of the perspective view independent of the dimensions of the orthogonal view on the base 18a. The sleeves 53a and 54a of the universal joints have been coupled by means of a coupling rod 64 pivotally connected at its ends to the sleeves. Every lateral movement of the rod 55, i.e., in a plane parallel to the base plane 18a is transmitted by means of the coupling rod 64 to the rod 56 while every movement of the rod 55 in a plane perpendicular to the base 18a is transmitted by means of the shaft 50 to the rod 56. The instrument 32 is also in this case provided with adjustment means in order to permit the exact adjustment of the distance of the pivot point 59 from the base 18a.

I claim:

1. A device for preparing perspective views from orthogonal views, comprising a flat base plate defining a base plane and a drawing board defining a projection plane, the base plate and drawing board being substantially at right angles to each other, and a guide rod having one end universally pivotally connected to a mounting in a tracing instrument carrying a tracing index which is located adjacent to the base plate and on a line extending through the pivot point of such mounting and perpendicular to the base plate, such mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, wherein the improvement comprises a shaft which is rotatable on a fixed axis extending parallel to the base plate, a universal joint on one end of the shaft in which the guide rod is slidably mounted, and a universal joint connecting the other end of the shaft to a rod extending parallel to the guide rod and having an end provided with a stylus for marking on the drawing board, the two rods being pivotally connected to the two ends of a coupling rod extending parallel to the shaft.

2. A device for preparing perspective views from orthogonal views, comprising a flat base plate defining a base plane and a drawing board defining a projection plane, the base plate and drawing board being substantially at right angles to each other, and a guide rod having one end universally mounted in a support located at one end of the base plate, having its other end provided with a stylus for marking on the drawing board, and having an intermediate portion slidably supported in a universally pivotable mounting in a tracing instrument carrying a tracing index which is located adjacent to the base plate and on a line extending through the pivot point of such mounting and perpendicular to the base plate, such mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, wherein the improvement comprises a slidably mounted bridge extending over the base plate, and a support for the tracing instrument which is mounted to slide on the bridge in a direction at right angles to the sliding movement of the bridge.

3. A device according to claim 2 wherein the support for the end of the end of the guide rod is adjustable in a direction perpendicular to the base plate.

4. A device according to claim 2 wherein an index is provided to denote the position relative to the base plate of a line perpendicular to the base plate extending through the point about which the end of the guide rod pivots in the support. 

1. A device for preparing perspective views from orthogonal views, comprising a flat base plate defining a base plane and a drawing board defining a projection plane, the base plate and drawing board being substantially at right angles to each other, and a guide rod having one end universally pivotally connected to a mounting in a tracing instrument carrying a tracing index which is located adjacent to the base plate and on a line extending through the pivot point of such mounting and perpendicular to the base plate, such mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, wherein the improvement comprises a shaft which is rotatable on a fixed axis extending parallel to the base plate, a universal joint on one end of the shaft in which the guide rod is slidably mounted, and a universal joint connecting the other end of the shaft to a rod extending parallel to the guide rod and having an end provided with a stylus for marking on the drawing board, the two rods being pivotally connected to the two ends of a coupling rod extending parallel to the shaft.
 2. A device for preparing perspective views from orthogonal views, comprising a flat base plate defining a base plane and a drawing board defining a projection plane, the base plate and drawing board being substantially at right angles to each other, and a guide rod having one end universally mounted in a support located at one end of the base plate, having its other end provided with a stylus for marking on the drawing board, and having an intermediate portion slidably supported in a universally pivotable mounting in a tracing instrument carrying a tracing index which is located adjacent to the base plate and on a line extending through the pivot point of such mounting and perpendicular to the base plate, such mounting being adjustable in the tracing instrument in a direction perpendicular to the base plate, wherein the improvement comprises a slidably mounted bridge extending over the base plate, and a support for the tracing instrument which is mounted to slide on the bridge in a direction at right angles to the sliding movement of the bridge.
 3. A device according to claim 2 wherein the support for the end of the end of the guide rod is adjustable in a direction perpendicular to the base plate.
 4. A device according to claim 2 wherein an index is provided to denote the position relative to the base plate of a line perpendicular to the base plate extending through the point about which the end of the guide rod pivots in the support. 